This invention relates to devices for sensing or detecting the number of cigarettes (or other rod-like articles) forming an orderly group of cigarettes housed in a tubular pocket and intended to be packed, said detecting devices comprising a detecting or feeler head provided with a plurality of feeler pins parallel to one another and slidably mounted so as to move axially and resiliently in said detecting head with an arrangement corresponding to that of the cigarettes forming the group of cigarettes, said detecting head with its feeler pins being softly pressed against the substantially co-planar facing ends of the cigarettes, whereby the feeler pins engaging a cigarette will resiliently collapse and the absence of collapse will indicate the absence of the respective cigarette in the group of cigarettes and will generate a "defect" electric signal that can be used in any suitable manner, for example to discard later on the package containing said defective group of cigarettes.
In some conventional detecting devices of the type specified above, each feeler pin has associated therewith an electrical contactor that will be closed when the feeler pin engages a cigarette and is, therefore, displaced toward the interior of the detecting head. All these electrical contactors are serially connected with each other and form a part of an electrical circuit that will remain in the opened condition when even one feeler pin does not engage a cigarette and, therefore, is not displaced so as to close the contact associated therewith.The absence of a cigarette, therefore, causes the detecting circuit to remain opened, and this electrical condition is stored in a memory means to cause, the package having the defective group of cigarettes to be discarded.
In another conventional sensing device of the specified type, the feeler pins that engage the cigarettes are resiliently displaced by the latter and remove screens that normally prevent suitable light beams (emitted, for example, by suitable sources such as light emitting diodes) from impinging on light-responsive elements, such as phototransistors, so as to create an electrical signal indicating whether the condition of the detected cigarette group is regular.
The invention is not concerned with the operation and devices by means of which the feeler pins generate a signal indicating whether the condition of the detected group of cigarettes is regular or defective, that is, whether the required number of cigarettes is present or whether even one cigarette is absent. The invention, instead, deals with another problem concerning the detecting devices as specified above. In fact, in the known devices of this type, the axes of the feeler pins are substantially in register with the axes of the positions where the cigarettes should be theoretically. It may happen, however, that in case one or more cigarettes are absent, the other cigarettes of the group will assume positions so as to engage all the feeler pins,i.e., so that one or more cigarettes are engaged by two feeler pins. In this circumstance, the detecting device would issue a wrong response, indicating a regular group of cigarettes, i.e., formed by the pre-established entire number of cigarettes, even if one or more cigarettes are missing.
The object of this invention is to eliminate this drawback, that is, to improve the detecting devices of the specified type so as to assure at all times a correct response concerning whether the number of cigarettes forming the detected group of cigarettes is complete or incomplete.
This object is achieved by this invention by locating some of the feeler pins of the detecting head excentrically with respect to the prospective positions of the cigarettes of the orderly group of cigarettes, rather than exactly coaxially with respect to said pre-established positions, so that if one or more cigarettes are absent and the remaining cIgarettes are misplaced, none of the latter can be engaged by two feeler pins simultaneously.